Conventional systematic therapy

Systemic therapy can be delivered using injections or tablets that have a general effect on the body. Conventional systemic therapies are highly effective, but they also involve a higher risk of side effects. Systemic medications are recommended for patients with moderate to severe psoriasis. Patients on systemic therapy are required to have their blood and blood pressure tested at regular intervals.

Methotrexate is a cytostatic and immunosuppressing agent. It is used in injections or tablets. Methotrexate is given to patients with advanced psoriasis, also accompanied by psoriatic arthritis. Patients receiving methotrexate should be carefully monitored because of serious side effects associated with this therapy, including anaemia and liver damage. Patients on methotrexate should undergo blood tests every 2-3 weeks. If reasonable caution is exercised, methotrexate-based therapy can quickly and significantly improve the symptoms of psoriasis. However, methotrexate does suppress the immune system and can only be administered to otherwise perfectly healthy individuals (free from any infections). Methotrexate is contraindicated during pregnancy (or period of trying to become pregnant). Because of safety concerns, methotrexate is also contraindicated in patients with severe kidney failure, bone marrow conditions, and gastric conditions, including  gastric and duodenal ulcers.

Retinoids have been used in the treatment of psoriasis since mid-1970s. Derived from vitamin A, retinoids normalise skin cell production and scaling. There are either natural or synthetic retinoids (retinol). Oral retinoids are recommended for patients with moderate and severe psoriasis who fail to respond to other therapies. The properties of retinoids are similar to those of vitamin A. Acitretin is one of the most commonly used retinoids. Discontinuation of the therapy may induce psoriasis flare-ups. Acitretin should not be used by pregnant women or women planning to get pregnant within 3 years following the use of this therapy.